The blimp you photographed is actually a Zeppelin. Well, not exactly like the impressive Zeppelins of the 1920's or '30's, but a zeppelin never the less. Unlike blimps, the one you photographed has a rigid structure. On the other hand, blimps are more like bullet-shaped balloons that are inflated to give it its shape.

The one you saw is owned by a company who gives aerial tours of parts of California by airship. It is great that you were able to photograph it.